This is Steven Salzberg's blog on genomics, pseudoscience, medical breakthroughs, higher education, and other topics, including skepticism about unscientific medical practices. Here's where I can say what I really think about abuses and distortions of science, wherever I see them.

Controversial GMO corn study being retracted over the authors' objections

Retractions are always interesting. When a scientific paper is retracted, it usually means the authors have found a serious error, and that the major conclusions are no longer valid. The error can be unintentional, but in some high-profile cases, the story is far more interesting.

Reading about a retraction is, for a scientist, kind of like reading about a celebrity divorce. You know something went wrong, and it just might be a bit scandalous.

Last year, I wrote a detailed takedown ("Does genetically modified corn cause cancer?") of a very poorly done scientific study by Gilles-Eric Seralini and colleagues, in which they claimed that genetically modified corn, Roundup Ready® corn, caused cancer in rats. The study had many egregious flaws, and I explained a few of them after reading the paper. Hundreds of other scientists criticized the study at the time, and six French science academies took the unusual step of issuing a joint statement that rejected the study's conclusions.

Among the many flaws, the study used far too few rats to make statistically valid conclusions, and it contained self-contradictory results, such as data showing that rats fed the highest amount of GMO corn lived longer than rats fed the lowest amounts. They also used a strain of rats that is highly prone to cancer. Basically, it was unconvincing junk science.

Last week, Retraction Watch reported that this paper is being retracted. Particularly interesting was the news that the retraction is being made by the editors of the journal, not by Seralini and his co-authors, who are pretty darned upset about it. The journal conducted a lengthy investigation (much too lengthy, I might add - they should have been able to act more quickly) and decided that the many flaws in the paper mean that its major findings are not valid. It is very unusual for editors to force a retraction like this, especially when fraud is not involved. The journal, Food and Chemical Toxicology, issued a statement that said:

"A more in-depth look at the raw data revealed that no definitive conclusions can be reached with this small sample size regarding the role of either NK603 [RoundupReady corn] or glyphosate [Roundup] in regards to overall mortality or tumor incidence. Given the known high incidence of tumors in the Sprague-Dawley rat, normal variability cannot be excluded as the cause of the higher mortality and incidence observed in the treated groups."

In other words, the editors concluded that Seralini's results were not supported by the data. Together with the rest of their statement, it seems pretty clear the editors are admitting that they screwed up during the peer review process, and they never should have published the article.

But is this grounds for retraction? Lots of bad science gets published, often due to sloppy peer review, and most of these papers aren't retracted. In this case, it's pretty clear that the high-profile nature of the paper played a role. Seralini is part of an anti-GMO organization, CRIIGEN, which has used this paper as justification for an aggressive campaign to ban GMO crops in Europe and elsewhere.

As bad as this study is, and as much as I'd like to see it retracted, I'm not sure that the justification given by the editors of Food and Chemical Toxicology is sufficient for retraction. Maybe it's because their statement is too carefully worded - wimpy, in fact. If they just came out and stated clearly that the study's conclusions are erroneous, then they would have a much better case for forcing the retraction. But they don't quite say that.

Here's what they are trying to say: "we screwed up and did a shoddy job in the peer review process, and now we realize that we never should have published this piece of dreck. Now we want to retract it so that no one will associate our journal with this bad science."

I know some very good scientists who have retracted papers merely because they couldn't replicate the results, and they grew worried that something was wrong. That's how science should work: rather than publish something erroneous, most scientists will admit their errors and retract their findings, or at least issue a correction. Obviously, Seralini has no plans to do this. His intent on publishing this paper was to make a political point, not a scientific one, and he distorted his findings in the paper itself, overstating his results with insufficient statistical evidence, and more so in statements to the press.

Retractions are indeed interesting. I'm still not sure the journal did the right thing to retract this paper, but I know they never should have published it in the first place.

(And for those who don't have time to look at the controversy after the original study: no, genetically modified corn does not cause cancer. Not even a little bit.)

4 comments:

What a load of croc. All Seralini did was to take the initial experiment published by Big Ag Company M and others and push it to it's logical conclusion. The parameters were those set up by Big Ag Company M in the first place. Seralini is being blamed for the bad study, when the blame should rest with Big Ag Company M who conducted the study initially, then published their findings only after something like 6 months of testing. It was a study by Big Ag Company M meant to dupe people into believing GMO are safe with little regard to actually finding the truth.

All Seralini did was bust them on their efforts to dupe the world by showing what would happen if Big Ag Company M's team had allowed the study to run the full length of the rats' lives.

No wonder Seralini is pissed, he's become the scapegoat. And Big Ag Company M looks like the poor victim again.

I think it's good that this article is being retracted. That other bad articles aren't retracted is NO excuse not to retract this article, it would better if more bad article would be retracted. The editors did make the proper decision.

Unfortunately some people, such as the previous commenters, want to politicize this incident. Regardless of one's opinion of a certain corporation's policy/behaviour research should comply with the methodological standards of science. One might object to Monsanto or genetic engineering in general on ethical or moral grounds, but one is not permitted to abuse science to bolster one's ideological position.

Anonymous II :How 'bout "any legitimate mechanism as to how said corn would cause said cancer"? Please explain in detail how genetically modified plant DNA causes "cancer" in mammalian cells -- I'll even let you exclude the deleterious effects of digestion on said DNA. I know you have no concept -- let alone any legitimate proof -- but it would be of great entertainment value to see you try and explain such, sans the hyperbole.

Now, go back to the Puff Ho and leave the science to those with functioning cerebral hemispheres.